New to this, so bear with me...

I just inherited a S7-200 from a former coworker. It's a 226 CPU with 243-1 Ethernet module and a bunch of 221 I/O modules.

There's no documentation of what has been done with the PLC - I have no idea what IP address was assigned, or what code has been downloaded to it.

When I power up the unit, the red SF (system fault) LED lights up on the Ethernet module. The CPU is in "Stop" mode. I can't connect to it from Micro/Win.

As a side note, when trying to set the PG/PC interface in Micro/Win, if I go into "Diagnostics" I get the error "s7_sr.dll not found". I was told that I shouldn't need this to connect over Ethernet.

Is there a way to reset the device back to factory settings? Failing that, I guess my other option is to locate/make a PPI cable and try to connect to my PC that way.

Thanks a lot!

 

If you want the PPI cable you will have to buy it, as it is actually a converter, not just a cable.

Also, there is a small toggle switch which is used to set processor mode. This is in different spots on differnt processors, sometimes under a cover. Have a look for this and check the position against the S7-200 manual.

 

Hi,

You won't be able to connect to the CPU through the Ethernet module unless it is correctly configured. You need to connect to the CPU first using a PC/PPI cable.

It sounds like you have corrupted Step7 MicroWin installation anyway, so the best thing is to re-install it, get the latest version. (A version is available free from the Siemens website, which lasts for 60 days or 100 activations.)

Once that is working, and you are connected to the CPU, use the ETHERNET configuration wizard to set up the CP243 module.

Download and consult the fine manuals from the Siemens site.

http://www.siemens.com/s7-200

Marc Sinclair
http://www.germainesystems.co.uk/

 

Found the toggle switch. Labels were worn off...

I was under the impression that the PPI cable was basically an RS485 converter; is this not true? Reference: http://www.plctalk.net/qanda/showthread.php?s=&threadid=9799 (message #4)

Thanks!

 

I'm sorry, I don't know if the RS-232 / PPI cable is a simple RS485 converter or not.

I don't know what Siemens charges for them now, but when I bought one they were less expensive than most typical PLC programming adaptors. If you have any S7-300/400 PLCs in your plant, some of the programming adaptors for those will also work with the S7-200.

One more thing, if you eventually acquire an RS-232 / PPI cable, I have found it necessary with some laptops to turn off the power saving features to get communications to work reliably.